Label-free DNA sensors using ultrasensitive diamond field-effect transistors in solution
Label-free DNA sensors using ultrasensitive diamond field-effect transistors in solution
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DOI：
10.1103/physreve.74.041919
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发表时间：
2006-10-01
影响因子：
2.4
通讯作者：
Kawarada, Hiroshi
中科院分区：
文献类型：
--
作者：
Song, Kwang-Soup;Zhang, Gou-Jun;Kawarada, Hiroshi
电荷检测生物传感器是近年来生物传感器研究的热点，尤其是场效应晶体管(FET)具有体积小、成本低、高输入、低输出阻抗等优点，可以实现简单、稳定的活体诊断系统。然而，最近对使用硅基离子敏感场效应管(ISFET)进行无标记DNA杂交电荷检测的可能性和局限性进行了关键的评估。这些器件的沟道表面必须覆盖相对较厚的绝缘层(SiO_2、Si3N_4、Al_2O_3或Ta_2O_5)，以防止溶液中的离子入侵。这些厚的绝缘层不适合DNA的电荷检测和小型化，因为厚的绝缘层的小电容限制了DNA负电荷从电解液到沟道表面的转移。为了克服这些困难，应该开发薄栅绝缘体FET传感器。在这里，我们报告了钻石溶液栅场效应晶体管(SGFET)，其中DNA固定的通道直接暴露在没有栅绝缘体的电解液中。这些SGFET在钻石(>；3.0V)的大电势窗口内稳定工作。因此，沟道表面不需要覆盖厚厚的绝缘层，DNA直接通过胺位置固定，这比现有的Si-ISFET DNA传感器灵敏度高30倍。钻石SGFET可以快速检测互补的3-聚体错配(10 PM)，并有可能检测单碱基错配的寡核苷酸DNA，而不会通过循环重复杂交和变性进行生物降解。
Charge detection biosensors have recently become the focal point of biosensor research, especially field-effect-transistors (FETs) that combine compactness, low cost, high input, and low output impedances, to realize simple and stable in vivo diagnostic systems. However, critical evaluation of the possibility and limitations of charge detection of label-free DNA hybridization using silicon-based ion-sensitive FETs (ISFETs) has been introduced recently. The channel surface of these devices must be covered by relatively thick insulating layers (SiO2, Si3N4, Al2O3, or Ta2O5) to protect against the invasion of ions from solution. These thick insulating layers are not suitable for charge detection of DNA and miniaturization, as the small capacitance of thick insulating layers restricts translation of the negative DNA charge from the electrolyte to the channel surface. To overcome these difficulties, thin-gate-insulator FET sensors should be developed. Here, we report diamond solution-gate FETs (SGFETs), where the DNA-immobilized channels are exposed directly to the electrolyte solution without gate insulator. These SGFETs operate stably within the large potential window of diamond (> 3.0 V). Thus, the channel surface does not need to be covered by thick insulating layers, and DNA is immobilized directly through amine sites, which is a factor of 30 more sensitive than existing Si-ISFET DNA sensors. Diamond SGFETs can rapidly detect complementary, 3-mer mismatched (10 pM) and has a potential for the detection of single-base mismatched oligonucleotide DNA, without biological degradation by cyclically repeated hybridization and denature.